on one's toes

每日一詞---on one's toes

on one's toes 就是指保持警覺、機敏，也就是能夠隨時行動的意思。比如在樂團，演奏者反應要快，才能跟上指揮：In Orchestra players must be on their toes all the time, so as not to miss an entrance.

這個片語也可以用在運動上，比如拳擊手或賽跑的人都要很機靈，才能隨時出手(或出腳xD)，和對手過招。當然，用它來形容上課也是可以的；比如上某些老師的課，學生總得聚精會神，以防突然被點到回答問題：I have to be on my toes in her class. I have to listen and think.